Question

1. choose the group that does not contain isotopes of the same element. (a) atom i: # of protons 18, # of neutrons 18; atom ii: # of protons 18, # of neutrons 19 (b) atom i: # of protons 25, # of neutrons 30; atom ii: # of protons 25, # of neutrons 31 (c) atom i: # of protons 37, # of neutrons 42; atom ii: # of protons 37, # of neutrons 41 (d) atom i: # of protons 82, # of neutrons 126; atom ii: # of protons 81, # of neutrons 126 use the diagram below to answer question 20. the letter n in

s²np¹\ represents an integer, where n = 1, 2, 3...etc. the families in the periodic table are labeled letters q - y in the periodic table above. 20. the electron configuration of the valence electrons of an atom in its ground state is ns²np¹. this atom is a group ______ element. (a) q (b) r (c) s (d) t

Explanation:

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

• Option A: Both atoms have 18 protons (same element), different neutrons (18 vs 19).
• Option B: Both atoms have 25 protons (same element), different neutrons (30 vs 31).
• Option C: Both atoms have 37 protons (same element), different neutrons (42 vs 41).
• Option D: Atom I has 82 protons, Atom II has 81 protons. Different number of protons means different elements.

Answer:

D. Atom I has 82 protons, Atom II has 81 protons. Different number of protons means different elements.